<!DOCTYPE html>
<html>
<head>
    <meta charset='utf-8'/>
    <title></title>
    <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no'/>
    <script src='../assets/mapbox-gl-dev.js'></script>
    <link href='../assets/mapbox-gl.css' rel='stylesheet'/>
    <style>
        body {
            margin: 0;
            padding: 0;
        }

        #map {
            position: absolute;
            top: 0;
            bottom: 0;
            width: 100%;
        }
    </style>
</head>
<body>

<style>
    .map-overlay {
        font: 12px/20px 'Helvetica Neue', Arial, Helvetica, sans-serif;
        position: absolute;
        width: 200px;
        top: 0;
        left: 0;
        padding: 10px;
    }

    .map-overlay .map-overlay-inner {
        background-color: #fff;
        box-shadow: 0 1px 2px rgba(0, 0, 0, 0.10);
        border-radius: 3px;
        padding: 10px;
        margin-bottom: 10px;
    }

    .map-overlay-inner fieldset {
        border: none;
        padding: 0;
        margin: 0 0 10px;
    }

    .map-overlay-inner fieldset:last-child {
        margin: 0;
    }

    .map-overlay-inner select {
        width: 100%;
    }

    .map-overlay-inner label {
        display: block;
        font-weight: bold;
        margin: 0 0 5px;
    }

    .map-overlay-inner button {
        display: inline-block;
        width: 36px;
        height: 20px;
        border: none;
        cursor: pointer;
    }

    .map-overlay-inner button:focus {
        outline: none;
    }

    .map-overlay-inner button:hover {
        box-shadow: inset 0 0 0 3px rgba(0, 0, 0, 0.10);
    }
</style>

<div id='map'></div>
<div class='map-overlay top'>
    <div class='map-overlay-inner'>
        <fieldset>
            <label>Select layer</label>
            <select id='layer' name='layer'>
                <option value='water'>Water</option>
                <option value='building'>Buildings</option>
            </select>
        </fieldset>
        <fieldset>
            <label>Choose a color</label>
            <div id='swatches'></div>
        </fieldset>
    </div>
</div>

<script>
    mapboxgl.accessToken = 'pk.eyJ1IjoibWFvcmV5IiwiYSI6ImNqNWhrenIwcDFvbXUyd3I2bTJxYzZ4em8ifQ.KHZIehQuWW9AsMaGtATdwA';
    var map = new mapboxgl.Map({
        container: 'map',
        style: 'mapbox://styles/mapbox/light-v9',
        center: [12.338, 45.4385],
        zoom: 17.4
    });

    var swatches = document.getElementById('swatches');
    var layer = document.getElementById('layer');
    var colors = [
        '#ffffcc',
        '#a1dab4',
        '#41b6c4',
        '#2c7fb8',
        '#253494',
        '#fed976',
        '#feb24c',
        '#fd8d3c',
        '#f03b20',
        '#bd0026'
    ];

    colors.forEach(function (color) {
        var swatch = document.createElement('button');
        swatch.style.backgroundColor = color;
        swatch.addEventListener('click', function () {
            map.setPaintProperty(layer.value, 'fill-color', color);
        });
        swatches.appendChild(swatch);
    });
</script>

</body>
</html>
Copy example